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Élaboration d'une méthode tomographique de reconstruction 3D en vélocimétrie par image de particules basée sur les processus ponctuels marqués

机译:基于标记点过程的粒子图像测速断层扫描3D重建方法的开发

摘要

The research work fulfilled during this thesis fits within the development of optical measurement techniques for fluid mechanics. They are particularly related to 3D particle volume reconstruction in order to infer their movement. This volumetric measurement technic, called Tomo-PIV has appeared on 2006 and has been the subject of several works to enhance the reconstruction, which represents one of the most important steps. The proposed methods in Literature don’t necessarily take into account the particular form of objects to reconstruct and they are not sufficiently robust to deal with noisy images. To deal with these challenges, we propose a tomographic reconstruction method, called (IODPVRMPP), which is based on marked point processes. Our method allows solving the problem in a parsimonious way. It facilitates the introduction of prior knowledge and solves memory problem, which is inherent to voxel-based approaches. The reconstruction of a 3D particle set is obtained by minimizing an energy function, which defines the marked point process. To this aim, we use a simulated annealing algorithm based on Reversible Jump Markov Chain Monte Carlo (RJMCMC) method. To speed up the convergence of the simulated annealing, we develop an initialization method, which provides the initial distribution of 3D particles based on the detection of 2D particles located in projection images. Finally, this method is applied to simulated fluid flows or real ones produced in an open channel flow behind a turbulent grid. The results and the comparisons of this method with a state-of-art algebraic algorithm show the great interest of this parsimonious approach.
机译:本论文完成的研究工作符合流体力学光学测量技术的发展。它们特别与3D粒子体积重建有关,以推断其运动。这种称为Tomo-PIV的体积测量技术已于2006年问世,已成为加强重建的几项工作的主题,这是最重要的步骤之一。文献中提出的方法不一定要考虑要重建的物体的特定形式,并且它们的鲁棒性不足以处理嘈杂的图像。为了应对这些挑战,我们提出了一种基于标记点过程的断层摄影重建方法,称为(IODPVRMPP)。我们的方法允许以简约的方式解决问题。它有助于引入先验知识并解决存储问题,这是基于体素的方法所固有的。通过最小化定义标记点过程的能量函数,可以获得3D粒子集的重建。为此,我们使用基于可逆跳跃马尔可夫链蒙特卡罗(RJMCMC)方法的模拟退火算法。为了加快模拟退火的收敛速度,我们开发了一种初始化方法,该方法基于对位于投影图像中的2D粒子的检测来提供3D粒子的初始分布。最后,该方法适用于在湍流网格后面的明渠流中模拟的流体流或真实的流体流。该方法的结果以及与最新代数算法的比较显示了这种简化方法的极大兴趣。

著录项

  • 作者

    Ben-Salah Riadh;

  • 作者单位
  • 年度 2015
  • 总页数
  • 原文格式 PDF
  • 正文语种 fr
  • 中图分类

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